Generally, the touch panel is one of a variety of devices for providing interfaces between users and information and communications devices which use a variety of displays. Specifically, the touch panel is an input unit through which the user can interface with the information and communications device by directly touching its screen with their finger or pen.
The touch panel allows users to interactively and intuitively operate a computer or the like simply by touching buttons displayed on its display with their finger so that men, women, and children can easily use it as an input device. Thus, the touch panel is applied to a wide variety of fields such as PDAs, LCDs, CRTs, equipment for banks or public offices, various medical equipment, travel guides, guidance equipment for main facilities, and transportation guides.
Operating or implementing types of the touch panel include a resistive (or conductive) film type, an ultrasonic type, and an infrared matrix type. The conductive film type touch panel has a panel structure with a chemical agent coated between a glass and a thin film and thin metal plates attached to X and Y-axis sides of the panel. When power is supplied to a panel of this type, a specific resistance is created through the panel. Then, if a finger or other object touches a position on the panel, the chemical agent reacts to instantly change resistance at the position. The resistance change is detected at the metal plates on the sides of the panel and the coordinates of the touched position are determined from the detected resistance change.
The infrared matrix type touch panel has horizontal and vertical infrared emission and detection arrays that are arranged on four sides of the panel to produce infrared rays in the shape of very close cross stripes on the panel. When an object touches a position on this panel, the object blocks an infrared ray that passes through the touched position and the blocking is detected to acquire position information of the touching object.
The infrared type touch panel is generally constructed as follows. A controller is provided on one portion of a PCB plate and a display part is provided on the other portion of the PCB plate. A non-reflective acrylic plate is provided on the front of the display part. A plurality of pairs of horizontal infrared emitting and receiving elements are provided on upper and lower edges of the display part and a plurality of pairs of vertical infrared emitting and receiving elements are provided on left and right edges of the display part to create an infrared matrix. A screen is provided on the rear of the display part. When a user touches a portion of the infrared matrix formed by the infrared emitting and receiving elements with their finger, an infrared ray at the touching portion is blocked to detect the position of the portion. The infrared matrix is controlled by the controller formed on one portion of the PCB plate.